This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. During RNA virus infection, double stranded RNAs (dsRNA) generated during RNA replication are potent molecular patterns recognized by innate immune receptors. We are interested in the molecular mechanism of the two such receptors, RIG-I and MDA-5. We aim to understand how RIG-I and MDA5 specifically recognize their receptors by determining the structure of the full length receptors alone and in complex with RNA.